title: Effect of overexpression of kinase- or RNase-deficient OsIRE1 on the endoplasmic reticulum stress response in transgenic rice plants.
abstract: IRE1 is an endoplasmic reticulum (ER) stress sensor protein in eukaryotes. In this study, we generated transgenic rice plants overexpressing three types of OsIRE1, including wild-type OsIRE1 (IRE1-OE) and two disrupted-IRE1s deficient in either kinase activity (K519A-OE) or RNase activity (K833A-OE), under the control of a constitutive promoter. Overexpression of wild-type IRE1 induced the ER stress response in transgenic rice even under non-stress conditions, whereas K519A-OE and K833A-OE had dominant negative effects on endogenous OsIRE1 expression in these transgenic plants. These lines exhibited phenotypes that were quite similar to those of OsIRE1 knock-down rice. These observations suggest that the two types of functionally disrupted OsIRE1 proteins behave as competitive inhibitors toward the ER stress response in transgenic rice plants. Furthermore, OsIRE1 may have a vital, as yet unidentified function, as determined through the characterization of the transgenic plants generated in this study.
authors.affiliation: Functional Transgenic Crops Research Unit; Genetically Modified Organism Research Center; National Institute of Agrobiological Sciences; Kannondai,Tsukuba, Ibaraki, Japan.
authors.forename: Yuhya
authors.initials: Y
authors.lastname: Wakasa
authors.forename: Shimpei
authors.initials: S
authors.lastname: Hayashi
authors.forename: Fumio
authors.initials: F
authors.lastname: Takaiwa
mesh_terms: D059865:Endoplasmic Reticulum Stress / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D005822:Genetic Vectors; D012275:Oryza / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D011494:Protein Kinases; D012260:Ribonucleases
keywords: IRE1; OsbZIP50; dominant negative; endoplasmic reticulum stress; rice (Oryza sativaL)